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Message-Id: <20190718024133.3873-1-leonardo@linux.ibm.com>
Date: Wed, 17 Jul 2019 23:41:34 -0300
From: Leonardo Bras <leonardo@...ux.ibm.com>
To: linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc: Leonardo Bras <leonardo@...ux.ibm.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
Mike Rapoport <rppt@...ux.ibm.com>,
Michal Hocko <mhocko@...e.com>,
Pavel Tatashin <pasha.tatashin@...cle.com>,
Jérôme Glisse <jglisse@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Pasha Tatashin <Pavel.Tatashin@...rosoft.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: [PATCH 1/1] mm/memory_hotplug: Adds option to hot-add memory in ZONE_MOVABLE
Adds an option on kernel config to make hot-added memory online in
ZONE_MOVABLE by default.
This would be great in systems with MEMORY_HOTPLUG_DEFAULT_ONLINE=y by
allowing to choose which zone it will be auto-onlined
Signed-off-by: Leonardo Bras <leonardo@...ux.ibm.com>
---
drivers/base/memory.c | 3 +++
mm/Kconfig | 14 ++++++++++++++
2 files changed, 17 insertions(+)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index f180427e48f4..378b585785c1 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -670,6 +670,9 @@ static int init_memory_block(struct memory_block **memory,
mem->state = state;
start_pfn = section_nr_to_pfn(mem->start_section_nr);
mem->phys_device = arch_get_memory_phys_device(start_pfn);
+#ifdef CONFIG_MEMORY_HOTPLUG_MOVABLE
+ mem->online_type = MMOP_ONLINE_MOVABLE;
+#endif
ret = register_memory(mem);
diff --git a/mm/Kconfig b/mm/Kconfig
index f0c76ba47695..74e793720f43 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -180,6 +180,20 @@ config MEMORY_HOTREMOVE
depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
depends on MIGRATION
+config MEMORY_HOTPLUG_MOVABLE
+ bool "Enhance the likelihood of hot-remove"
+ depends on MEMORY_HOTREMOVE
+ help
+ This option sets the hot-added memory zone to MOVABLE which
+ drastically reduces the chance of a hot-remove to fail due to
+ unmovable memory segments. Kernel memory can't be allocated in
+ this zone.
+
+ Say Y here if you want to have better chance to hot-remove memory
+ that have been previously hot-added.
+ Say N here if you want to make all hot-added memory available to
+ kernel space.
+
# Heavily threaded applications may benefit from splitting the mm-wide
# page_table_lock, so that faults on different parts of the user address
# space can be handled with less contention: split it at this NR_CPUS.
--
2.20.1
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